merging multiple gps tracks into more accurate single track

Merging multiple gps tracks into more accurate single track how to#

Merging multiple gps tracks into more accurate single track how to#

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Other GPS devices combine the advantages of the two different methods by measuring altitude barometrically and then repeatedly comparing it with GPS data. The Russian counterpart to the American navigation satellites, which is actually called NAVSTAR, fills the occasional gap in the satellite network, especially in Eurasian and Asian regions. However, devices with both GPS and GLONASS can often remedy this. Even though they don’t need to be calibrated, GPS devices may not be as accurate in remote, isolated (mountainous) regions. If you are more interested in absolute elevation, GPS is the better choice.

For longer trips, we recommend verifying the elevation data at huts or on maps to get the best results. However, as mentioned above, it is imperative to calibrate the devices beforehand in order to receive precise data.

The fluctuations are much smaller and the accuracy is better than GPS-based devices. In sum, barometric altimeters are great if you’d like to know the elevation profile of your route. A barometer can make reliable short-term weather predictions that can be incredibly useful for mountaineers. However, it’s important to mention that some devices have integrated storm warning systems: if the air pressure drops rapidly, this usually means that a low pressure area is approaching, which often leads to bad weather. If the air pressure varies as a result of these factors, it’s better to use GPS. In such a case, a barometric altimeter would be even more inaccurate than GPS.Įxample 3: You tend to go on adventures in places where the weather and temperature play a major role:Īs was already touched upon, the weather and temperature can have a major impact on air pressure. If you don’t have a known position at which you can recalibrate the device, the error could continue and the deviation could even increase. With a barometric measurement, it’s possible that the device was calibrated incorrectly after the first day, resulting in a deviation of 20 metres for every subsequent measurement. A GPS-based device may only be able to determine the elevation with an accuracy of 20 to 25 metres, but your position is constantly recalculated and the error will be balanced out in most cases. The actual altitude is not usually the most important factor for such excursions, so you don’t have to calibrate your device beforehand.Įxample 2: If you’re going on day-long trips with major differences in altitude (a thousand metres or more) and would like to know the altitude of your current position:įor this purpose, we would recommend using a GPS-based device. When the weather conditions are relatively stable, atmospheric pressure is a reliable source for elevation calculations and perfect for calculating elevation gain and loss. Your device would measure the air pressure in defined time intervals, thereby determining differences in elevation and subsequently adding them together. Here are some examples of possible uses and the best device for those particular activities:Įxample 1: You’re a mountain biker or hill walker and would like to know how much elevation you’ve gained over the course of your outing:įor this purpose, a barometric altimeter would clearly be your best choice. In our opinion, that depends entirely on what you plan on using it for. All these things can have such a negative impact on the accuracy of your positioning and altitude that they can even result in deviations of up to 100 metres. Plus, the signal can also be reflected off walls. Even a dense forest can weaken the signal. Clouds weaken the signal, while deep canyons can even isolate the receiver altogether. This is due to the fact that a GPS signal behaves physically similar to light. However, if your device only finds four satellites, it is possible that both your positional and altitudal information will strongly deviate from the reality of the situation. If there are several available satellites, the receiver will be able to pick and choose, giving you the best and strongest signals. The accuracy of this geodetic triangulation of your location also depends to a large extent on the quality of the signal. However, in order to receive information about your current altitude, the receiver requires a signal from at least 4 satellites. The exact position of the device is determined by means of signals from various satellites in earth’s orbit. The Garmin Montana 610 with a barometric altimeterĪs the name suggests, GPS devices use the American Global Positioning System (GPS).